The potential effect of low cell osmolarity on cell function through decreased concentration of enzyme substrates.

J Exp Bot

Division of Plant Science, University of Dundee, The James Hutton Institute, Invergowrie, Dundee, UK.

Published: September 2018

Some freshwater algae have lower (<130 osmol m-3) intracellular osmolarities than most others (>180 osmol m-3). Low osmolarities are related to the presence of flagella and the low energy cost of active water efflux following downhill water influx unconstrained by cell walls covering the plasmalemma, and the low resource cost of cell wall synthesis with the same mechanical degree of safety. One consequence of low intracellular osmolarity is limitation on the concentration of metabolites, that is, substrates and products of enzyme activity. Models of the flux through metabolic pathways, and hence the specific growth rate, using steady-state concentrations of enzymes and metabolites have involved organisms with intracellular metabolite osmolarities >280 osmol m-3, where the metabolite concentrations are much greater than the total osmolarity of some freshwater algae. Since the protein concentration (mol m-3) in the cells and the specific growth rates of freshwater cells with low and with higher intracellular osmolarity are highly similar, the models of trade-offs between enzyme and metabolite concentrations for cells with high intracellular osmolarity need modification for cells with low intracellular osmolarity. The soluble free-radical scavenger ascorbate can constitute as little as 0.2% of the low intracellular metabolite concentration (mol m-3) of low-intracellular-osmolarity cells.

Download full-text PDF

Source
http://dx.doi.org/10.1093/jxb/ery254DOI Listing

Publication Analysis

Top Keywords

intracellular osmolarity
16
low intracellular
12
freshwater algae
8
osmol m-3
8
specific growth
8
intracellular metabolite
8
metabolite concentrations
8
concentration mol
8
mol m-3
8
cells low
8

Similar Publications

Propagation of membrane tension mediates mechanical signal transduction along surfaces of live cells and sets the time scale of mechanical equilibration of cell membranes. Recent studies in several cell types and under different conditions revealed a strikingly wide variation range of the tension propagation speeds including extremely low ones. The latter suggests a possibility of long-living inhomogeneities of membrane tension crucially affecting mechano-sensitive membrane processes.

View Article and Find Full Text PDF

Type III protein secretion systems (T3SSs) function as multiprotein devices that span the envelope of Gram-negative bacteria using the peptidoglycan (PG) layer as scaffold. This spatial arrangement explains why modifications in PG structure can alter T3SS activity. In incorporation of non-canonical D-amino acids in the PG was shown to decrease the activity of the T3SS encoded by the pathogenicity island-1 (SPI-1) without affecting other T3SS, like the flagellum apparatus.

View Article and Find Full Text PDF

Succinate Nanomaterials Boost Tumor Immunotherapy via Activating Cell Pyroptosis and Enhancing MHC-I Expression.

J Am Chem Soc

January 2025

State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.

Despite the promising clinical applications of immunotherapy, its effectiveness is often limited by low immune responses and tumor immune escape. In this study, we introduce a simple and drug-free inorganic nanomaterial, sodium succinate (CHNaO NPs), prepared using a rapid microemulsion method to enhance cancer immunotherapy. The synthesized CHNaO NPs can release high concentrations of Na and succinate ions into tumor cells, leading to an increase in intracellular osmolarity.

View Article and Find Full Text PDF

A cell's global physical state is characterized by its volume and dry mass. The ratio of cell mass to volume is the cell mass density (CMD), which is also a measure of macromolecular crowding and concentrations of all proteins. Using the Fluorescence eXclusion method (FXm) and Quantitative Phase Microscopy (QPM), we investigate CMD dynamics after exposure to sudden media osmolarity change.

View Article and Find Full Text PDF

Effect of osmotic pressure on membrane permeation through antimicrobial peptide-induced pores.

Biochem Biophys Res Commun

January 2025

Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, Shizuoka, 422-8529, Japan; Nanomaterials Research Division, Research Institute of Electronics, Shizuoka University, Shizuoka, 422-8529, Japan; Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka, 422-8529, Japan. Electronic address:

Most antimicrobial peptides (AMPs) induce membrane damage such as pore formation in bacterial cells, resulting in rapid cell death. On the other hand, bacterial cells have a large intracellular turgor pressure, i.e.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!